This invention relates to a heat exchanger mounting for use on gas turbine engines.
In gas turbine installations it is common to use a heat exchanger so that the hot exhaust gases can heat the incoming combustion air. In general such heat exchangers have cores which provide two separate flow paths therethrough, the flow paths being separated by thin walls. Combustion air under high pressure from a compressor flows through one path while the low-pressure, hot exhaust gas flows through the other path, the heat from the exhaust gas being given up through the separating walls to the combustion air.
When gas turbines are operated intermittently and under varying power conditions, as is usual in vehicle engines, the heat exchanger is subjected to great variations in temperature of the exhaust gases, which causes large transient thermal growths in the core, ducting and support structures and resultant stresses in and between these elements. In addition, normal vehicle operation will impose vertical, fore-and-aft, and sidewise vibration and shock loads on the heat exchange units.
In the past, gas turbine heat exchangers have been mounted by using sheet metal ducting between the heat exchanger and engine body for the low-pressure exhaust gas. The high-pressure combustion air ducting has included spring compensated bellows to absorb relative expansion and limit pressure, thermal and other loads imposed on the heat exchanger. These systems are complicated, difficult to analyze for loads and, therefore, not an ideal solution with high reliability.